New CTPS protocol for assessing varietal tolerance to beet viral yellows presented to the CIRAA in Montpellier
The 13th International Conference on Pests and Auxiliaries in Agriculture (CIRAA) was held at the Institut Agro Montpellier from 29 to 31 October.
This was an opportunity for GEVES to present the results of the PNRI project, Yellows Resistbeet, on the development of new protocols for assessing the varietal resistance/tolerance of sugar beet to viral yellows, in inoculated field trials or under controlled conditions.
This project, led by GEVES in partnership with ITB, contributed to the development of a field protocol to assess varietal tolerance/resistance to 3 major yellows viruses (BChV, BMYV and BYV) in trials inoculated with viruliferous aphids, with the following deliverables:
Optimisation of a routine production method for viruliferous aphids (Myzus persicae), to inoculate with BYV, BChV and BMYV respectively in the field or in insect-proof tunnels:
- Selection of inoculation parameters guaranteeing homogeneous infestation of the viruses and significant discrimination of symptoms and yield between inoculated and healthy modalities for these 3 viruses.
- Development of a multiplex RT-qPCR method to detect and identify the 4 viruses BYV, BChV, BMYV and BtMV and validation of inoculated trials using this method.
- Selection of the most relevant criteria for assessing varietal tolerance, in particular sugar yield in conditions with and without viral yellowing.
- Development of CTPS decision support tools to define the rules for including a variety tolerant to the 3 viruses in the French Catalogue:
- Html documents summarising the results of statistical analyses and graphs by virus, with different statistical models, depending on the study by site and by virus or on the grouping of sites either annually or multiannually.
- R-Shiny application to vary yield loss acceptance threshold changes.
Since 2022-23, this genetic lever has been used to assess varietal tolerance/resistance when registering varieties in the French Catalogue, and should make it possible, in the short to medium term, to promote varieties with good agronomic performance and low yield losses in conditions with and without viral yellows for these three viruses. It will be essential to combine this genetic lever with other agro-ecological levers to provide an efficient and sustainable integrated pest management system.
In addition, GEVES has developed spatial mixed statistical models incorporating yellows covariates to improve yield parameter estimation in VSCU trials with heterogeneous yellows outbreaks resulting from natural contamination.
In addition, this project was also an opportunity for GEVES-SNES to develop a test for varietal resistance to BtMV in the greenhouse, which can be offered as a service or as an additional experiment.